AZOSPIRILLUM plays a significant role in the quantitative and qualitative enhancement of crop yield. Its isolates, however, exhibit extreme differences as reflected in their impacts on crop yield. In this study, isolates of AZOSPIRILLUM were initially compared with respect to their morphological traits and such growth promoting characteristics as nitrogen fixation; solubility of insoluble phosphorus; and their auxin, sidrophore, hydrogen cyanide (HCN), and ACC-deaminas enzyme production. Furthermore, five isolates characterized by superior growth promoting characteristics were investigated for their effects on yield and its components in wheat Morvarid cultivar. For this purpose, an experiment was conducted in a randomized complete block design with 6 bacterial treatments including five AZOSPIRILLUM isolates and one control treatment (without bacterial inoculation) with 4 replicates at Iraqimahaleh Station, Golestan Agricultural and Natural Resources Research Center, where the soil is classified in the large Torriorthents Group. Results of seed inoculation in selected isolates showed that the impacts of different AZOSPIRILLUM isolates on wheat yield components such as panicle length, peduncle length, number of seeds per panicle, number of panicles per square meter, weight of 1000 seeds, seed yield, and straw yield were statistically significant at 1% confidence level, as evidenced by increases of 14. 91, 47. 94, 25. 98, 24. 97, 82. 86, 20. 42, and 37. 88%, respectively, in the above traits of Mordavid cultivar relative to those of the control with no inoculation.

AZOSPIRILLUM is a well-studied genus of plant growth-promoting bacteria. Phytohormone production by PGPR is considered as one of the effective factor to increase the tomato yield significantly. In order to study the effect of AZOSPIRILLUM inoculant on on Growth Characteristics and Yields of Tomato, three strain of AZOSPIRILLUM were isolated, identified, and purified from Tehran suburb soils. Tomato seeds were inoculated by those isolated strains of AZOSPIRILLUM and tomato seedlings were grown under the greenhouse condition. At the end of grown periodof tomato plant, stem length, root length, leaf and branch fresh weight, root fresh weight, root bulk, leaf and branch dry weight and root dry weight were measured. The results showed that tomato seed inoculation had significant effect on all measured characteristics except the length of root. Inoculation of tomato seed with AZOSPIRILLUM increased the bulk and dry weight of root and consequently it attributed to increased uptake of plant nutrient. It seems that AZOSPIRILLUM inoculants have a beneficial effect on tomato growth.

Arospirillum is one of the plant growth-promoting bacteria which is in the rhizosphere and the intercellular of the cereals and other plant roots. One of the characteristics of this bacterium, considered in this study, was its effect on the germination ability of inoculated seeds. In this research, 58 Arospirillum isolates were isolated from 38 samples of soils and canola roots from the different regions of Golestan province, Iran and then they were compared to select superior growth promoting isolates. The effect of inoculation with 4 superior isolates along with control (no ninoculated) was evaluated on some germination parameters of canola seeds (Hayola 401) in randomized complete block design (RCBD) with 8 replications. Results showed that germination percentage, average of germination time and germination rate were significantly different (p<0.01) among various isolates. The inoculation of canola seeds germination percentage and germination rate decreased and germination time increased as compared to the control. AC34-III isolate produced the minimum amount of auxin, so the lowest germination percentage and germination rate were attributed to it compared with other isolates. Moreover the higher auxin- producing isolate (Ac43-III) showed the maximum germination percentage that was introduced as the best bacterial treatment.

Bacteria of the genus AZOSPIRILLUM are well known as plant growth promoting rhizobacteria. The ability to synthesize phytohormones is considered one of the most important mechanisms to promote plant growth and is widely distributed among plant associated rhizobacteria. The most important phytohormone produced by AZOSPIRILLUM is the auxin indole-3-acetic acid, with the L-tryptophan as the precursor. In the present study, we evaluate the capacity of eight AZOSPIRILLUM strains isolated from rice and wheat, to producein vitro auxins using plant exudates. Our results show that isolates produced auxins in tryptophan free media, but, generally, the amount produced increased when the tryptophan concentration increased. Some plants root exudates had a similar effect to tryptophan for the auxin production. In this sense, bean, rice and canola root extracts produced, respectively, 93.3%, 96.2%, and 88.31% more auxin than L-tryptophan.AZOSPIRILLUMsp. isolate A3 had the maximal capacity to produce auxin. Therefore, the effect of cell free supernatant was studied on rice root development. Statistical analysis did not show any significant difference between root number and dry weight of the treated and control seedlings. However, significant differences were observed in root length and wet weight at a=0.01 and a=0.05, respectively.

AZOSPIRILLUM is a gram negative plump and straight rods bacterium. 4 Tehran forest parks were selected: (Chitgar, Sohanak, Sorkhehhesart, and Toska) in order to AZOSPIRILLUM isolation. Two samples are provided from each park, one of them from forested zones and the other from non forested Zone. NFb (Nitrogen Free malat) semisolid medium and RC (Rodriquez Caceres) used for culturing. The biochemical tests used for separation species. AZOSPIRILLUM species were isolated in these soils. Our researches showed three species  A.brasilense, A. lipoferum and A. irakense. Microbial population is determined by MPN (Most Probably Number) method. In average, the amount of population in forested zones is 4.3×105 and in non forested zones is 1.43×105 (bacterial cell in each grams of soil (CFU/g)) by solid NFb medium. In average, the population in forested zones is 1.91×105 and in non forested zones is 0.77×105 by solid RC medium. In average, the population in planet forested zones and in non forested zones were 0.95×103 and 0.27×103 by semisolid NFb medium. Then the Nitrogen fixation ability of acquired samples was studied. In this way, by use of Rennin Media and Gas Chromatography and by transformation Acetylene to Etilen the Nitrogenase of sample were determined. Acetylene reduction in A. lipoferum was highest in comparison with other species and was 86.27 nmol/24hTube and A. irakense was least in comparison with other species and was 23.92 nmol/24hTube and A. brasilense was 56.4 nmol/24hTube.

Introduction: Polyhydroxyalkaniates (PHAS) are bacterial polymers that are formed as naturally occurring storage polyesters by a wide range of microorganisms usually under unbalanced growth conditions. Mechanical properties of PHAS make them suitable replacements for petrochemically produced bulk plastics (polyethylene, polypropylene etc.), but in contrast to these commodity plastics PHA are completely degradable to carbon dioxide and water through natural microbiological mineralization. PHAS can be produced by biotechnological processes under controlled conditions. Polyhydroxybotyric acid (PHB) was the first of the PHAS discovered and is the most abundant polyester found in bacteria.Materials and methods: First, a rich bacterial suspension prepared from poly(3-hydroxybutyrate), then the cells were broken down and ensure the absence of live cells. The cell free enzymes were added to M9 medium. Then the sample turbidity was measured at a wavelength of 600 nm and incubated at 30°C and centrifiuged at 120rpm. Next, the amount of PHB as well as solution turbidity were measured and compared with control. The physical and chemical analyzes of extracted PHB samples such as UV absorbtion, FTIR, HPLC and HNMR assesed and compared with standard sample.Results: In twelve days this experiment was conducted, from the third day, the amount of polyhydroxybutyrate was measurable and the highest polyhydroxybutyrate was gained on the tenth day. The level of PHB was constant. Moreover, the level of glucose was decreased gradually till the tenth day. By Physico-chemical analysis, production of polyhydroxybutyrate was approved.Discussion and conclusion: In this experiment, the reaction efficiency was 37.5 percent. Probably the rest of glucose could be changed to other intermediate compounds by other enzymes in the sample. Therefore, by purification of the enzyme, usage of specific substrate and optimization of conditions outside the cell could help the production of polyhydroxybutyrate continually. Production is very cost-effective, by this method.